QuestionA company has been monitoring their sales, and based on the history of data collected, they can provide the following probability distribution for the number of sales per week per salesperson. What is the sales per week per person standard deviation? (Round to the nearest two decimal places) \begin{tabular}{cc} \hline Number of sales per week & Probability $\mathrm{f}(\mathrm{x}$ \\ \hline 0 & 0.09 \\ 10 & 0.15 \\ 20 & 0.42 \\ 30 & 0.26 \\ 40 & 0.08 \\ \hline \end{tabular}